mAh

The number of mAh shows the capacity of the battery: a battery with more mAh can be used for a longer period before it needs to be recharged. The number of mAh does not need to be the same as your current battery; batteries of the same type are compatible irrespective of the number of mAh. A higher number of mAh does not mean any additional 'load' on your equipment.

Some manufacturers use mWh or Wh instead of mAh. This unit easily converts to mAh; see the following example:

A battery indicates: 3200 mWh (or 3.2 Wh) and a voltage of 6,4 V.
This equals: 3200 / 6,4 = 500 mAh.